Inverted incandescent mantle.



C. W. DAVIS. INVERIED lNCANDfiSCENT MANTLE.

APPLICATION FILE D DEC. 18, I914.

Patented Nov. 5,1918.

1 UNITED STATES PATENT OFFICE.

CORTLAND V7. DAVIS, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE MANTLE LAMP COM- PANY OF AMERICA, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

INVERTED INCANDESCENT MANTLE.

To aZZ whom it may concern:

Be it known that I, CORTLAND ,W. DAVIS,

'a citizen of the United States, residing at of incandescent structures or mantles for lighting purposes, and especially for burners of the inverted type. The invention relates more particularly to improved means for forming the cellulose structures of the mantle.

In inverted mantles it is desirable that the lower end thereof shall be symmetrical and preferably semi-spherical in form to give a maximum efiiciency in light. The well known IVelsbach' process of making mantles of this character, consists in impregnating a structure of fibrous cellulose with solution of refractory earths, then igniting the fibrous structure and thereafter shaping the resulting refractory earth structure over a suitable flame. The dimensions of the finished structure are, generally about of the impregnated cellulose structure and this finished structure is very similar in shape to the cellulose structure. It is desirable, therefore, to produce a cellulose structure of a form and size which will result in a desired shape in the finished article. 7 V

The usual method of forming the cellulose structure for inverted mantles has been to attach one end of a tubular knitted fabric to a suitable carrier or support, such as a lava collar, and to close the other, or lower, end of the fabric. Various means have been employed to close this lower end. One manner has been to close the lower end of the tubular knitted structure by drawing the edges toward the center and either bunching and tying witha string, or passing a string through the loops of the knitting and drawing the loop string together. In either case the fabric is bunched together around the center and is very ObJGCtIODablG, not 1nfrequently increasing the weight of the.ma-.

terial at the center to such an extent as to result in sagging out of symmetrical form, and weakening the material of the mantle. Moreover, the end of an inverted mantle is Specification of Letters Patent.

Patented Nov. 5, 1918.

Application filed December 18, 1914. Serial No. 877,983.

the point from which the maximum light can be obtained. The bunching of the material at this point reduces the efliciency of the mantle. Various methods of goring have been employed to obviate the foregoing objections, but when suflicient gorin has been done to produce a symmetrical c losed end,

the large number of seams found necessary,

become objectionable. It has also been proposed to close the end of this tubular knitted structure by sewing into it a fiat elliptical piece of the same knitted structure, the shape of the ellipse being designed to neutralize the unequal, longitudinal and transverse shrinkage of the knittin in the impregnated fabric when burned, and to thereby produce a section practically circular in form at the lower end of the mantle, after the mantle material shall have been shrunk by the burning of the fibrous structure. This method, however, involves mechanical difliculties and requires skill to properly sew the elliptical section to the tubular section. Difiiculty is encountered also, in proportioning the axes of the ellipse so as to take care of all the conditions that vary the shrinkage of the fabric.

Prior to this invention it has never been feasible in constructing inverted mantles, to sew a circular piece of fabric to a tubular knitted fabric in forming the end of an inverted mantle, because of the unequal shrinkage of the fabrics portion.

This invention retains the advantageous features of the former methods, and cially that method which attaches one piece of fabric to another by a single circular seam, and at the same time eliminates the disadvantages of the prior methods of producing mantles, wherein an elliptical section is sewed to the bottom of a tubular section- This invention comprises the production of an incandescent inverted mantle having a substantially cylindrical or tubular body section, the upper end of which is suitably segenerally used in the end.

espe-' cured to a carrier whereby the mantle may sewing a circular piece of fabric at substan-' tially right angles to the tubular body sec? tion, the essential feature of the invention residing in the provision of this closing disk from a. fabric which will shrink uniformly in all directions when the fibrous structure of the mantle is burned.

The shrinkage of the knitted fabric from which the tubular body section may be made is unequal in the directions of length and width. and should the lower circular ends be made from the same material as the tubular section, it would result in a finished mantle with a distorted lower end, due to the unequal distribution of the threads resulting from the knitting of the fabric.

Figure 1 is a perspective view of a section of tubular fabric.

Fig. 2 is a detail view, greatly enlarged, of a section of the fabric of Fig. 1, shown knitted.

Fig. 3 is a plan view of a circular section of fabric.

Fig. i is an enlarged plan view of woven fabric of Fig. 3.

Fig. 5 is an enlarged plan view of another embodiment of woven fabric.

Fig. (3 is a side elevation of a mantle.

To produce the lower end for a mantle which symmetrical in shape and which will give the maximum ctticiency in light, I have provided an end member 1 circular in shape and of different material from the tubular member 2, when constructed of knitted material. whereby the tubular and end members will shrink diiferently during the. burning of the mantle. resulting in an end substantially parabolic in form and free from thickened material except at the sides of the mantle. flue means of accon'iplishing this result. resides in making the tubular member of knitted fabric 3. as heretofore and the circular and member shown in Fig. may be of woven fabric. such as at in Fig. l, or at, in Fig. 5. The end member 1 may be secured to the tubular member 2 by any suitable means, such as by sewing the parts together, as indicated by the seam This seam may be a single, circular seam. It is obvious that the tubular member 2 may be formed of the material of Fig. 5. and the member 1 formed of the material of Fig. l, or the tubular member :2 and the end member 1 may be formed of the same material as either '-l or However, it is preferred to construct the substantially circular end member of Fig. 3 from the material of Figs. 4. or 5, and such woven material is preferably constructed so that it is substantially the same number of cords or threads to the inch measured on any two axes at right angles to each other.

The resulting mantle, therefore, is composed of a plurality of parts, the fibrous cellulose structure of which may be of differentmaterials. producing a substantially symmetrical mantle after shrinkage.

Copies of this patent may be obtained for five Having l'lltli described my invent-ion, what 1 claim as new and desire to secure by Letters Patent is:

1. An inverted incandescent mantle comprising a tubular body portion of fabric of unequal longitudinal and transverse shrinkages and a closed end portion made from fabric of substantially the same number of threads to a given space measured on any two axes at right angles to each other where by the fabric is of substantially equal longitui'linal and transverse shrink-ages.

A. cellulose structure for an inverted incandescent mantle composed of a tubular body portion and acircular end portion. said end portion being attached to said tubular body port ion. the fabric in said end portion being constructed of woven fabric so that in the incincrating process of treat ing the mantle the shrinkage of said end portion is substantially equal longitudinally and transversely.

An inverted mantle formed from a tubular knitted member and a circular end member of woven material united to the tubular member.

i in inverted mantle having a tubular body of knitted fabric the major portion of its threads running lengthwise of the tube. and an end member formed from a single piece of woven material the threads of which are substantially at right angles to each other. 7

o. n invertci'l mantle having a tubular body of knitted fabric the major portion of its threads running lengthwise of the tube, and an end member formed from a circular piece of woven materal. said woven material being composed of threads having sub stantially the same number of threads to a given space n'ieasured on any two axes at right angles to each other. i

(l. A mantle structure including drical body portion and a closure body portion composed of crossed parallel threads.

T. A mantle structure including a cylindrical body portion and a closure for said body portion COD'IPOSQfl of crossed rows of evenly spaced parallel threads.

8. A fabric mantle. having a cylindrical body section, and a closure. for one end of said body section, said closure having threats which are so laid that there are equal lengths of thread across similar dimensions of the-closure.

In testimony whereof. I aflix my signature. in presence of two witnesses.

CORTLAND XV. DAVIS.

a cylin for said rows of ll itnesses C. S. SMITH, ll. S. Pnnsna.

cents each, by addressing the Commissioner of Patents,

Washington, D. G. 

